Аннотация:It is shown that the shape of the spectrum of a radiating object and the angular distribution of the radiation intensity strongly influence the magnitude of the ’relativistic searchlight’ effect. The modulation of the observed spectral density of the flux from the short-period binary due to Doppler effects and light aberration can vary by a factor of 2-4 as compared to bolometric flux observations. The effect can exceed 1 percent for binaries with a radial velocity semiamplitude of 150 km/s. For the optical radiation of AO 620-00, the effect is about 1.5 percent; for radiation of the low-mass component of Geminga, it is about 10 percent.